The mechanical assembly of two parts or elements may be achieved in many various ways. One of the simplest ways which takes up the smallest amount of space is the use of a coupling of the bayonet type comprising on one of the elements a projecting pin, and on the end of the other element a socket having a slot for receiving and locking the pin.
Couplings of this type are well known and employed in many fields. However, they are reserved for the connection of elements intended to remain stationary since they can only ensure with difficulty the reliable transmission of a torque, above all if the latter is large.
For the purpose of ensuring an assembly of complete reliability, the most currently employed means are for example: collars, screw-and-nut systems or other systems. Their drawbacks are that they require precise moving operations and the application of well-determined clamping forces which create possible errors in the positioning.